The present invention relates to a method for monitoring for leaks in subsea pipelines. More particularly, the present invention relates to a method for monitoring for remote leaks in subsea offshore pipelines constructed as a pipe-in-pipe flowline with the product transported in the inner pipe.
Offshore hydrocarbon recovery operations are increasingly pressing into deeper water and more remote locations. Here it is very expensive to provide surface facilities and it is desirable to minimize these requirements. Often satellite wells are completed subsea and are tied to remote platforms through extended subsea pipelines as a means to reduce the production cost. Even these platforms serving as central hubs in the offshore infrastructure are provided only the minimal facilities required for collecting and partially treating the well fluids before exporting them toward onshore facilities through yet more subsea pipelines. The subsea pipelines, both to and from the platform hubs, are crucial to this infrastructure. Further, such pipelines are measured in miles and tens of miles and although it is infrequent, these pipelines are subject to failure.
Thus, there is a clear need for a dependable and economical means for remotely monitoring for leaks in the pipelines and, in the event that a leak is detected, to determine the location of the leak for evaluation and/or repairs.